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From Igor Galić <>
Subject Re: 3.0, the 2011 thread.
Date Sat, 18 Jun 2011 18:39:08 GMT

----- Original Message -----
> On Friday 17 June 2011, Graham Leggett wrote:
> > We used openssl to make our non blocking event driven stuff work,
> > and it works really well (once you've properly handled
> > SSL_ERROR_WANT_READ and SSL_ERROR_WANT_WRITE). There is no reason
> > I can see that would stop us using openssl to be async in httpd,
> > we just need to refactor the mod_ssl code to actually do it.
> Someone (Paul?) once told me that openssl is not very good when it
> comes to async access to the session cache (which could need network
> io if using memcached), CRLs (which I could imagine to reside in
> and similar things. But this would have to be evaluated.
> > The tricky part with event driven code is the really bad support
> > for   event driven file access. We used libev as our core event
> > loop, which does a significant amount of work to make files and
> > sockets work the same way in the event loop as best it can in a
> > portable way. Don't know of any other event loop that does this.
> > It's difficult trying to do the event driven thing if you
> > intersperse event driven socket handling with blocking file
> > handling, you end up with many requests blocked by an unrelated
> > system call.
> Yes, I guess we would need a pool of lightweight worker threads that
> does the file io (especially sendfile). Those threads would probably
> get by with very small stack sizes and use little resources. If the
> event library we choose already has this built in, we can of course
> use that, too.

This kind of reminds me of the architecture of Apache Traffic Server


Igor Galić

Tel: +43 (0) 664 886 22 883

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